Thermoplastic vinyl tile products and production thereof

ABSTRACT

A combination of calcined attapulgite and platy talc is used as a reinforcing filler along with a calcium carbonate bulking agent in rigid, hard and durable asbestos-free thermoplastic vinyl tiles. The tiles are produced by the conventional hot calendering technique.

United States Patent 11 1 Burns 1 1 THERMOPLASTIC VINYL TILE PRODUCTS AND PRODUCTION THEREOF [75] Inventor: Robert A. Burns, Long Valley, NJ.

[73] Assignee: Engelhard Minerals & Chemicals Corporation, Edison, NJ.

[221 Filed: Oct. 4, 1974 [21] Appl. No.; 512,099

Related US. Application Data [63] Cuntinuati0nin-purt 0t Ser Nu. 424.337. Dec, 11).

1973. abandoned.

[52] US. CL... 260/311 R; 260/314 EP; 260/4249 [51] Int. C115... C08K 3/26; C(18K 3/34; COSK 7/00 {58] Field of Search... 260/4249. 31.2 R, 31.4 EP

[56] References Cited UNlTED STATES PATENTS 3.463.765 3/1913) Cote et 111. 2611/42 49 X 3.641.206 2/1972 Weitzel e1al......... 260/4249 X 1 1 Nov. 11,1975

OTHER PUBLICATIONS Sarvetnick, Polyvinyl Chloride (van Nostrand Rein hold, 1969), pp. 75. 81-82. 107-110. 145. 151. 219 244.

Penn, PVC Tea/inning (Wiley lntcrsciencc 3 ed. 1971), pp. 147-148, 188-190.

Primary Examn'nerMelvin Goldstein Assistant Et'uminer-T. De Bcnedictis, Sr. K111017161, Agent, or Firm-Melvin C. Flint; lncz L. Moselle 10 Claims, N0 Drawings ii l 1 lf,li-..-V

THBHMG SllC VINYL V i PRODUCTS v r nouuc mon mnlnzor RELATED APPLICATIONS rm application is a continuation-impart of my onpcnding appliqatbn, Sen No. 424M532, filed Doc. 0, 19 71 mmubandonell; t 1

lpaoitokounn or 'rne INVENTION The inwemion relates to mineral-titled rigid vinyl chloride tics of the type used for floor conning and partienlatlyito mhemmfren veinforcedrkinysl attest.

Jlihwprirmipal cabinet of the invention is to psovidouasbestow-flee minenal coinforoetl tiles which possess a speculum of woperties lmrctofore obtainable only whm'using asbestos fibers as a i'eiofiotcing agent. Anotho'robjeotlis topraduce tho mos'free tiles by sub jentim amtureof'vinyl polymernplasiioizeri mabiliunr niqt. plasticiaer and filler during hot calendcring, lnvarv g iably calcium carbonate is used as a bulking agent. Typical fomudatbns contain about 20% of a vinyl chloride-vinyl acetate oopolymcr and about 80% asbestos and mineral filler. Plasticizprs and resins are often 2 optionaily, kaolin clay. The anapuigite clay functions during hot ealendering to impart sufficient hot strength to the ather ingredients to avoid tearing.

From this bnief description of the invention it is ap parent that an essential feature of the invention resldes in the use oi'a three-componehtmineral filler for vinyl theslcalcined attapuigite is unsuitable as the sole filter. This type at elayhas unusualiy high oil abaorptivity. when used alone, the heat-activated clay would absorb an excessive amount ofplnstieizer, making prooesiing difficohorimpossibie. Sirnilavly'v, kaoiin clay and min are highly oil absorptive. When piaty talc andlot kaolin olayawmod with calcined attapulgitn in the absenea of calcium carbonate, calendaring aniihandling will be difficult and the tiles will have low impact and flexural strength. A. mixture of caioinod fltaptllgitn clay and calcinmnarbbnate without piety tum results in tiles which are stiff and have poor impact strength. n the other hand, tile nompnsiizkms prepared without heat activated-Wylie clay, using various combinations ofin'ithet conventional mineral fillcm iacliuding combiations of kaolin clay toalninedand uncailcimd) and calcium carbonate, lack the ability to maintain swongth at elevated temperature and the tiles do not possess lhe boquhitmnombinntihn of mommies Tiles promoted in Mme with this inven ion with combination of calcined aittanvlgite clay, calciumcarbonata ann tate display increased strength at room temperature and mai t in thsirmne h a elevat d i mnelwav r bhiAitflb uesciinnon Vinyl chloride polymers useful in practice of m invention include simple homopoiymers of vinyl chloride or copolymers, terpolymers or the like which possess adqedtoimpmvcfillctwettingandease oi glendefinfitbe essentifl properties of the polymericatructunu of :ical formulations for producing tuna cs are despy US. Pat. Na. 2,773,851 to Leqyl- Tolman. th e flooring tileg differ from the $131 1 ifi lii (Igor covetings available as sheet or tile which c ta ing; amounts of varlou s liiller a3; atesi; in some cam, sn'ial amounts 6' b e siin ov rnment has recently imposed limitations to the amount of air-borne asbestii's which i'priiiitf in a plant because of the potential health hazafd; ciated with asbestos. fine method iaietiniinating airborne agbestos is to eliminate the need for asbestos in lilf'as vinyl floor tiles. Fibroue fillers, notably the flbtous variety of talc and wood flour, one disclosed ilii the literature as being possible alternatives to the use of asbestos in rigid vinyl tileo it lsgenerally accepted, however, that asbestos is vastly aupevior m buch fibrous fille rs and to the best oi my knowledge all of the reinfoneedvinyl tile which is marketed in thii time is of the viii?! type.

SUMMARY OF THE I'NVENTKON The essence of the invention resides in the provision olllafill, ngia'r; mane meant-mutiny! the B? one ing as the filler the combination of l'feitfiatitlfiiitofl ampulgite clay, platy talc and the conventional calcium carbonate? milking agent, the combination of fillers constituting the major constituent, on a weight basis, of the vinyl tile composition. Optionally, te kaolin clay filler may be siihstituted for a portion ofthe talc.

An aspect of the invention involves the production of mineral-rcinfoicd asbestos tiles by hot iilehdering a suitable plasticized vinyl chloride polymer and a mixture of heat-activated attapulgite clay, platy talc and,

polyvinyl chlot dm Such copolymers and ternolymers con ain gtleasflqfi vinyl chloride. gnaw ng; a giv in V v- Serrano 3 3191 74 mime-amt n r c rinytchlnt wlanqyvinvlaccta tgsmi' n; atleast 1! main es PP JVW at 7 chlorid and 3 to v nyl acetate.

fesentatfve plasticizers are enumerated in US.

1 @311674 and the plasticizers listed therein mplgyed in praoticing thc invention. The most @innl-Plw wq 9 ar aati ttifi plas k chlotidg compositions s a miit'ure ot dioctyl tphthalate andcpoxi ized soya bean oil used in proporthus of approximately 1 part by weight Soya bean oil to 4 to 6 parts by weight dioctyl phthalate. Combinations of soya. bean oil with other plasticizers of the aromatic typ gg. bui l bcnzyl ph'thalat, are also ueetui. The .hsioT stabilizers in US. Pat. No. $,'37,674 is also incorporated herein by reference.

Normally a lubricant, usually nearic acid, is included in ihei'orrriulaiion to minimize adherence of the plasticized vinyl composition to the calerltli tolls. Alternatlvely a lubricant, e.g., a siticone oil, can be applied to 3b the eaiendeiea ieli's'.

(Georgia-Florida rollers earth) at a temperature in the nine of about 900" to 1200'F. to a volatile matter (V. below 10%, preferably 5% or less. The VM. or volatile matter of the raw earth as mined is usually -continued -continued Parts by Weight Parts (wt.)

I000 Chemcarb 66 250 Experimental formulations were produced using the EXAMPLE 1 same ingredients with the exception that various other in an illustrative example of the invention, tiles havfiller materials were substituted for the asbestos. in all big processing characteristics and properties (including 10 formulations calcium carbonate (Chemcarb" 66) was hardness, flexural and impact strength) at least as good used as a bulking agent. The total quantity of fillers in as those of current vinyl asbestos tiles were prepared all of the experimental formulations was selected to from the following formulation. maintain the same filler volume used in preparing the conventional (control) tiles and the total theoretical amount of oil absorbed was the same in all formula- Material Weight Percent tions Vinyl copolymer (85% vinyl 17.7 Fillers used in some of the experimental formulations Vinyl Meta) are identified as follows: gioct yl phthalate 6.2 Attach LVM l d It 1 l poxldlzed soybean oil Li Y ca cme a P" E e C y Nuos tabe Vl324 (stabilizer) M Satintone No. 2 calcined kaolin clay 22:3 :32 Emtal 500 platytalc I Chemcarb 66, 40.0 ASP 102 uncalcmed platy kaolin clay Emmi Details of the method for preparing the tiles are given Attaclay LVM 4,4

in Example 2 around limestone During processing of reinforced vinyl tiles it is imperm mi (calcined) ampulgm my ative that the formulation maintain its strength at high temperature (e.g., 300F.) to prevent the calendered i sheet from pulling apart. One of the functions of an as- The resm' plasuclzers and stabmzer were mixed bestos filler is to provide hot strength. To evaluate hot gether prior to addition of fillers. A two-roll mill with 30 strength the following test was Sci A inch hole was differential speed rolls of 20 and 25 r.p.m. was used for drilled into each tile specimen which was than compounding. The roll temperatures were adjusted to pended on a hook in a Despatch oven at for 2 2 (fast roll) and (slow 1ml) by steam heat hours. The hole distortion during oven aging serves to 8- i provide an indication of hot strength. Acceptable hot Approximately 600 gl'ams of compound with mgredi' strength was characterized by the substantial absence ents spatula mixed was placed into the nip of the f sag and d f ti rolls- The compound was Picked "P by the fast You and The following tests were carried out to compare the removed immediately with a take-05 blade Once the properties of the control (conventional) and expericompound had completely Passed through the mill: it 40 mental reinforced vinyl tiles. All specimens were equiliwas returned to the mill- This Procedure was repealed brated at 74F. and 48% relative humidity m at least Period of 4 mihhtes- 24 hours before testing.

The final sheet, approximately thickness. was Hardness was evaluated by the well-known Shore P p y P E the g P- The compound was D" test. Impact strength was measured by the lzod passed through the mill and immediately removed with method and also b h f fli n impact method the take-Off blade- (Fed. Method No. 3311). In the modified Federal test EXAMPLE H method, a 1-inch diameter steel ball weighing 0.143 pounds is dropped from a height of 20 inches (for Ma The following tests were carried out to demonstrate inch thickness tiles). Failure occurs when cracks are that asbestos-free Vinyl tiles eemparable ih Properties 0 observed after four or less ball impacts. Since all tiles to Vinyl asbesms tiles may be obtained y substituting passed this test, the height was changed to 30 inches to for the asbestos the combination of specific calcined permit discrimination between sampies. The number f Clay, namely calcined ahapulgite y and The drops (up to a maximum of 6) that were required to insults of the tests show also that tiles comparable to the dime failures were recorded f the 30 i h heighh [n vinyl asbestos tiles were not obtained when a variety of measuring fl properties, i Specimens (three other filler systems were substituted for the asbestos. paraiiei and three perpendicmar m the grain), h i x The formulation for the asbestos reinforced tiles, un- 45 i h were iesteii derstood to be typical of commercial formulations, was accordance i h F d l T M th d N 3131, as follows: the deflection of each specimen was determined using the lnstron Tester with crosshead speed of 2 inches per Parts (WL) minute and span length of 4 inches. This test measures PVC/PVA copolymer (85% vinyl 1 the distance that the specimen has deflected (or bent) chloride-15% vinyl acetate) at the moment it breaks up or slips through the sup- Dioctylphthal l .1 2 ports. Average values are reported. Since it is believed 53133:? soybean m 6 that this test has inherent deficiencies, the flexural Stearic acid I strength for each specimen was also determined. The 13:51:53? gg reported values are the average of six specimens and Filler are given in pounds per square inch (p.s.i.).

The results, summarized in table form, show that only the conventional tile formulation A (asbestos-carbonate filler) and the experimental formulations which contained calcined attapulgite clay (B, C and D) had acceptable hot strength. The other formulations sagged and/or deformed excessively when held at elevated temperature. Of the formulations containing calcined attapulgite clay, only the formulation containing a mixture of the calcined attapulgite clay with platy talc (B) had impact strength and flexural properties comparable to those of the asbestos-filled formulation. Thus, tiles produced with calcined attapulgite clay in the absence of talc (C and D) had low impact strength and, in the case of C, the tiles also had low flexural strength.

The data for test F (calcined kaolin clay filler) show that the tiles were lacking in hardness, impact strength and flexural properties. As mentioned, formulation F also lacked strength at elevated temperature.

S. The tile composition of claim 4 wherein the calcium carbonate is present in amount of about 30 to 50% based on the weight of the tile composition and said platy tale is present in amount of about 15 to 35% by weight of the tile composition.

6. The tile composition of claim 4 wherein said heatactivated attapulgite clay is present in amount in the range of about 4 to 10% based on the weight of the tile composition.

'7. The tile composition of claim 2 which contains from 2 to by weight of heat-activated attapulgite clay and from 15 to 35% by weight of a platy filler se lected from the group consisting of talc and mixtures of talc with up to 50% by weight of kaolin clay.

8. A reinforced thermoplastic vinyl chloride sheet composition which comprises about 16 to 18% by weight of a vinyl chloride-vinyl acetate copolymer containing at least 70% vinyl chloride, about 6 to 8% by EFFECT OF FILLERS ON PROPERTIES AND PROCESSING CHARACTERISTICS OF VINYL FLOOR TILES Parts by Weight Filler per 100 PVC/PVA Conventional Formulation Vinyl Tile of Subject Formulation Invention Formulations Outside Subject Invention Filler A B C D E F Asbestos 150 0 O 0 0 0 Calcium carbonate 250 225 230 290 204 250 Calcined attapulgite clay 0 25 105 0 0 Calcined kaolin clay 0 0 0 0 0 I50 Talc 0 155 0 0 210 0 Uncalcined kaolin clay 0 0 140 0 0 0 Properties Hardness, Shore D" 66 68 68 73 66 61 Impact strength Izod, ft.-lb.lin. 2.4 2.2 1.9 1.0 1.6 1.4 Falling ball, lb. drops at 6 6 6 Flexural properties Deflection, inches 1.39 1.47 1.44 1.46 1.44 1.45 Strength, p.s.i. 550 670 440 800 500 415 Hot strength A A A A F F A Acceptable F Failure I claim:

1. A reinforced thermoplastic vinyl chloride tile composition suitable for the manufacture of floor tile which comprises a minor weight proportion of a plasticized vinyl chloride polymer uniformly mixed with a major weight proportion of a mixture of finely divided mineral fillers. said mixture of fillers comprising, based on the total weight of said composition, 2% to 15% attapulgite clay which has been heat activated to a volatile matter content below 10% by weight, 15 to platy talc and 30 to 50% calcium carbonate, with the proviso that the combined amount of mineral fillers is in the range of about 55 to 85% of said total weight, said composition being free from asbestos.

2. The tile composition ofclaim 1 wherein said plasticized vinyl chloride constitutes about 20 to 30% by weight of the composition, the mixture of fillers consisting essentially of the balance.

3. The tile composition of claim 2 wherein said plasticized vinyl chloride constitutes about 24 to 26% of the weight of said composition and is a vinyl chloride-vinyl acetate copolymer containing at least 70% vinyl chloride.

4. The tile composition of claim 3 wherein said heatactivated attapulgite clay has an average particle size in the range of 3 to 20 microns and is present in amount in the range of about 2 to 15% based on the weight of the tile composition.

weight of a plasticizer composed of a combination of dioctyl phthalate and epoxidized soya bean oil, stabilizer, pigment and, as a filler, from 4 to 10% by weight of attapulgite clay heat-activated to a volatile matter below 5% by weight and in the form ofa powder having an average particle size below 20 microns, 35 to 40% by weight calcium carbonate and 25 to 30% by weight of a platy talc, said composition being essentially free from asbestos.

9. In a method for producing reinforced thermoplastic vinyl chloride wherein a plasticized vinyl chloride polymer is mixed with mineral fillers including a filler which functions as a reinforcing agent and provides hot strength and a filler which functions as a bulking agent, and the resulting tile composition is calendered between heated rolls to form sheets, the improvement whereby the desired hot strength and reinforcement are obtained without incorporating asbestos, which comprises utilizing as the filler a mixture of minerals consisting essentially of micron-size particles of attapulgite clay which has been heat activated to a volatile matter below 10% by weight, 15 to 35% platy talc and 30 to 50% calcium carbonate, said particles of attapulgite clay being present in amount within the range of about 2 to 15% based on the weight of the tile composition, with the proviso that the combined amount of mineral fillers is in the range of about 55 to of the weight of said composition.

10. The method of claim 9 wherein the mixture of constitutes from about 4 to 10% by weight of the filled mineral fillers constitutes from about 70 to 80% by composition.

weight of the filled composition and the attapulgite clay V 

1. A REINFORCED THERMOPLASTIC VINYL CHLORIDE TILE COMPOSITION SUITABLE FOR THE MANUFACTURE OF FLOOR TILE WHICH COMPRISES A MINOR WEIGHT PROPORTION OF A PLASTICIZED VINYL CHLORIDE POLYMER UNIFORMLY MIXED WITH A MAJOR WEIGHT PROPORTION OF A MIXTURE OF FINELY DIVIDED MINERAL FILLERS, SAID MIXTURE OF FILLE RS COMPRISING, BASED ON THE TOTAL WEIGHT OF SAID COMPOSITION, 2% TO 15% ATTAPULGITE CLAY WHICH HAS BEEN HEAT ACTIVATED TO A VOLIATILE MATTER BELOW 10% BY WEIGHT, 15 TO 35% PLATY TALC AND 30 TO 50% CALCIUM CARBONATE, WITH THE PROVISO THAT THE COMBINED AMOUNT OF MINERAL FILLERS IS IN THE RANGE OF ABOUT 55 TO 85% OF SAID TOTAL WEIGHT, SAID COMPOSITION EING FREE FROM ASBESTOS.
 2. The tile composition of claim 1 wherein said plasticized vinyl chloride constitutes about 20 to 30% by weight of the composition, the mixture of fillers consisting essentially of the balance.
 3. The tile composition of claim 2 wherein said plasticized vinyl chloride constitutes about 24 to 26% of the weight of said composition and is a vinyl chloride-vinyl acetate copolymer containing at least 70% vinyl chloride.
 4. The tile composition of claim 3 wherein said heat-activated attapulgite clay has an average particle size in the range of 3 to 20 microns and is present in amount in the range of about 2 to 15% based on the weight of the tile composition.
 5. The tile composition of claim 4 wherein the calcium carbonate is present in amount of about 30 to 50% based on the weight of the tile composition and said platy talc is present in amount of about 15 to 35% by weight of the tile composition.
 6. The tile composition of claim 4 wherein said heat-activated attapulgite clay is present in amount in the range of about 4 to 10% based on the weight of the tile composition.
 7. The tile composition of claim 2 which contains from 2 to 15% by weight of heat-activated attapulgite clay and from 15 to 35% by weight of a platy filler selected from the group consisting of talc and mixtures of talc with up to 50% by weight of kaolin clay.
 8. A reinforced thermoplastic vinyl chloride sheet composition which comprises about 16 to 18% by weight of a vinyl chloride-vinyl acetate copolymer containing at least 70% vinyl chloride, about 6 to 8% by weight of a plasticizer composed of a combination of dioctyl phthalate and epoxidized soya bean oil, stabilizer, pigment and, as a filler, from 4 to 10% by weight of attapulgite clay heat-activated to a volatile matter below 5% by weight and in the form of a powder having an average particle size below 20 microns, 35 to 40% by weight calcium carbonate and 25 to 30% by weight of a platy talc, said composition being essentially free from asbestos.
 9. In a method for producing reinforced thermoplastic vinyl chloride wherein a plasticized vinyl chloride polymer is mixed with mineral fillers including a filler which functions as a reinforcing agent and provides hot strength and a filler which functions as a bulking agent, and the resulting tile composition is calendered between heated rolls to form sheets, the improvement whereby the desired hot strength and reinforcement are obtained without incorporating asbestos, which comprises utilizing as the filler a mixture of minerals consisting essentially of micron-size particles of attapulgite clay which has been heat activated to a volatile matter below 10% by weight, 15 to 35% platy talc and 30 to 50% calcium carbonate, said particles of attapulgite clay being present in amount within the range of about 2 to 15% based on the weight of the tile composition, with the proviso that the combined amount of mineral fillers is in the range of about 55 to 85% of the weight of said composition.
 10. The method of claim 9 wherein the mixture of mineral fillers constitutes from about 70 to 80% by weight of the filled composition and the attapulgite clay constitutes from about 4 to 10% by weight of the filled composition. 